﻿/**
 * Created by 69023 on 2019-01-02.
*/

jQuery.base64 = (function ($) {

	var _PADCHAR = "=",
		_ALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
		_VERSION = "1.1";//Mr. Ruan fix to 1.1 to support asian char(utf8)


	function _getbyte64(s, i) {
		// This is oddly fast, except on Chrome/V8.
		// Minimal or no improvement in performance by using a
		// object with properties mapping chars to value (eg. 'A': 0)

		var idx = _ALPHA.indexOf(s.charAt(i));

		if (idx === -1) {
			throw "Cannot decode base64";
		}

		return idx;
	}

	function _decode_chars(y, x) {
		while (y.length > 0) {
			var ch = y[0];
			if (ch < 0x80) {
				y.shift();
				x.push(String.fromCharCode(ch));
			} else if ((ch & 0x80) == 0xc0) {
				if (y.length < 2) break;
				ch = y.shift();
				var ch1 = y.shift();
				x.push(String.fromCharCode(((ch & 0x1f) << 6) + (ch1 & 0x3f)));
			} else {
				if (y.length < 3) break;
				ch = y.shift();
				var ch1 = y.shift();
				var ch2 = y.shift();
				x.push(String.fromCharCode(((ch & 0x0f) << 12) + ((ch1 & 0x3f) << 6) + (ch2 & 0x3f)));
			}
		}
	}

	function _decode(s) {
		var pads = 0,
			i,
			b10,
			imax = s.length,
			x = [],
			y = [];

		s = String(s);

		if (imax === 0) {
			return s;
		}

		if (imax % 4 !== 0) {
			throw "Cannot decode base64";
		}

		if (s.charAt(imax - 1) === _PADCHAR) {
			pads = 1;

			if (s.charAt(imax - 2) === _PADCHAR) {
				pads = 2;
			}

			// either way, we want to ignore this last block
			imax -= 4;
		}

		for (i = 0; i < imax; i += 4) {
			var ch1 = _getbyte64(s, i);
			var ch2 = _getbyte64(s, i + 1);
			var ch3 = _getbyte64(s, i + 2);
			var ch4 = _getbyte64(s, i + 3);

			b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12) | (_getbyte64(s, i + 2) << 6) | _getbyte64(s, i + 3);
			y.push(b10 >> 16);
			y.push((b10 >> 8) & 0xff);
			y.push(b10 & 0xff);
			_decode_chars(y, x);
		}
		switch (pads) {
			case 1:
				b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12) | (_getbyte64(s, i + 2) << 6);
				y.push(b10 >> 16);
				y.push((b10 >> 8) & 0xff);
				break;

			case 2:
				b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12);
				y.push(b10 >> 16);
				break;
		}
		_decode_chars(y, x);
		if (y.length > 0) throw "Cannot decode base64";
		return x.join("");
	}


	function _get_chars(ch, y) {
		if (ch < 0x80) y.push(ch);
		else if (ch < 0x800) {
			y.push(0xc0 + ((ch >> 6) & 0x1f));
			y.push(0x80 + (ch & 0x3f));
		} else {
			y.push(0xe0 + ((ch >> 12) & 0xf));
			y.push(0x80 + ((ch >> 6) & 0x3f));
			y.push(0x80 + (ch & 0x3f));
		}
	}



	function _encode(s) {
		if (arguments.length !== 1) {
			throw "SyntaxError: exactly one argument required";
		}

		s = String(s);
		if (s.length === 0) {
			return s;
		}

		//s = _encode_utf8(s);
		var i,
			b10,
			y = [],
			x = [],
			len = s.length;
		i = 0;
		while (i < len) {
			_get_chars(s.charCodeAt(i), y);
			while (y.length >= 3) {
				var ch1 = y.shift();
				var ch2 = y.shift();
				var ch3 = y.shift();
				b10 = (ch1 << 16) | (ch2 << 8) | ch3;
				x.push(_ALPHA.charAt(b10 >> 18));
				x.push(_ALPHA.charAt((b10 >> 12) & 0x3F));
				x.push(_ALPHA.charAt((b10 >> 6) & 0x3f));
				x.push(_ALPHA.charAt(b10 & 0x3f));
			}
			i++;
		}


		switch (y.length) {
			case 1:
				var ch = y.shift();
				b10 = ch << 16;
				x.push(_ALPHA.charAt(b10 >> 18) + _ALPHA.charAt((b10 >> 12) & 0x3F) + _PADCHAR + _PADCHAR);
				break;

			case 2:
				var ch1 = y.shift();
				var ch2 = y.shift();
				b10 = (ch1 << 16) | (ch2 << 8);
				x.push(_ALPHA.charAt(b10 >> 18) + _ALPHA.charAt((b10 >> 12) & 0x3F) + _ALPHA.charAt((b10 >> 6) & 0x3f) + _PADCHAR);
				break;
		}

		return x.join("");
	}


	return {
		decode: _decode,
		encode: _encode,
		VERSION: _VERSION
	};

}(jQuery));